1. Field of the Invention
The present invention relates in general to a cost-effective low-risk system and method for enhancing the payload capacity, carriage efficiency and the adaptive flexibility of external airborne stores mounted on an aerial vehicle. More specifically, the present invention relates to a system and method for the conversion of current and prospective external fuel tanks into substantially conformal, diverse functionality, high capacity, high volume, and aerodynamically efficient, externally mountable airborne stores.
2. Description of the Related Art
The majority of military aerial vehicles, such as combat aircraft, attack helicopters and the like, are typically equipped with an external airborne stores suspension, delivery and release system. External airborne stores are devices intended for external carriage, mounted on aircraft suspension and release equipment and may or may not be intended to be separated in flight from the aerial vehicle. External airborne stores typically include missiles, rockets, bombs, nuclear weapons, mines, torpedoes, detachable fuel and spray tanks, chaff and flare dispensers, refueling pods, gun pods, electronic countermeasure (ECM) pods, electronic support measure (ESM) pods, towable target and decoy pods, thrust augmentation pods and suspension equipment, such as racks, eject launchers, drop launchers and pylons. The external stores are detachably installed on the aerial vehicle via specific suspension points, typically referred to as hard points or weapon stations, which are distributed across the external surface of the aerial vehicle in such a manner as to provide for the best possible performance of the stores carried and for the aerodynamically most advantageous flight conditions.
For economical efficiency, as well of for organizational and operational reasons, most military aerial vehicles are designed as multi-role platforms. Consequently modern military aircraft are provided with functional versatility, such as the capability of conducting a variety of missions, including offensive counterair (OCA), defensive counterair (DCA), interception (AA), combat air patrol (CAP), close air support (CAS), suppression of enemy air defenses (SEAD), deep strike, anti-shipping (AS), anti-submarine warfare (ASW), electronic warfare (EW), refueling, reconnaissance, surveillance, Unmanned Aerial Vehicle (UAV) launching, satellite launching or the combination of two or more of the above. Each specific mission profile requires weapon pairing or the assignment of optimal weaponry for the given mission. Weapon pairing involves the delivery of a particular load of a particular store or a specific mix of different store types and loads. The wide range of mission profiles required from modern military aerial vehicle necessitates the option of carrying a variety of stores and loads.
Modern multi-role aircraft are provided with weapon stations to accommodate a variety of stores required for the conduct of many different missions. Although the number of the available stations differs among different types of aircraft typically eight to twelve stations are provided. As payload space is at premium in a combat aircraft or in an attack helicopter, the location of the stations is typically limited to the external, lower surface of the aerial platform. Due to increased aerodynamic drag effects the external location of weapon stations carrying stores inevitably involves flight performance penalties, such as reduced maneuverability, airspeed, range, effective operational ceiling, increased fuel consumption and the like. Typical external weapon station locations include wing tip hard points, outer wing hard points, middle wing hard points, inner wing hard points, side fuselage hard points, fuselage center line hard points, and the like. Although each hard point allows for a limited set of options for the uploading of stores the overall stores configuration can be mixed or matched in accordance with the type of aircraft. An allowed combination of stores and loads in the framework of a single sortie is typically referred to as the external stores configuration. It is important to note that typically all stores on a particular hard point must be of the same type for a given configuration.
Thus, for example, an exemplary stores configuration could include medium-range missiles on the wing tip hard points, rocket pods on the outer wing hard points, bombs on he middle wing hard points, ECM pods on the inner wing hard points, short-range missiles on the side fuselage hard points, and external fuel tanks on the fuselage center line hard points. Although, the various types of stores deliverable and releasable by a single aerial platform is quite large, the number of possible stores configurations is substantially limited both by the number of weapon stations and by permissible weapon station loading options.
Typically, a military aircraft performing a long-range sortie or a mission involving an extended operational activity period, is equipped with auxiliary external fuel tanks, which are commonly secured to pylons suspended on specific hard points. Due to considerations concerning aerodynamic efficiency and the associated flight performance parameters the external fuel tanks are designed to have a suitable structural configuration, such as the characteristic torpedo shape. Typically external fuel tanks are manufactured in diverse sizes that allow for a wide range of fuel store capacities ranging from 67 to 1,360 US gallons per tank unit. External fuel tanks are usually the largest external payload carried by an aerial vehicle. The number of external drop fuel tanks carried by an aerial vehicle differs according to the vehicle type and the variants thereof, but typically one to five external fuel tanks are supported where two or four tanks are carried under the wings and one or two tanks are installed under the fuselage.
The delivery of aerial vehicles to a user (e.g. an Air Force) where the vehicle has the capacity of carrying external stores, such as weapon stores or fuel stores, inherently includes the provision of the optional external configurations where the carriage of the stores and the associated operation parameters were designed, tested and certified by the manufacturer prior to the operational fielding of the aerial vehicle. As a result, the aerodynamic and operational characteristics of a typical external fuel tank are optimal within the certified external configurations and in association with the aerial vehicle. The typical fuel tank characteristics include high capacity carriage, substantially flexible center of gravity limits and ranges, acceptable flutter, high load limits, positive dynamic separation and emergency release effects, known aerodynamic effects on the aircraft stability and maneuvering, known aerodynamic effects on the adjacent external stores and the like.
Note should be taken that certain external store types, such as multiple unit weapons, cluster bombs, ECM, ESM, and the like, are not provided with an optimal aerodynamic shape. Therefore, such weapon stores are aerodynamically unstable, produce increased drag and negative dynamic separation and release effects.
Strategic and tactical demands in concert with the ever-accelerating pace of technological progress motivate a continuous program of improvements in the operational capacity of military aerial vehicles. Although the development of a completely new aerial platform is an extremely long and highly expensive process, substantial enhancement to the capabilities of an existing platform can be accomplished by progressive development and new operational implementation of new/upgraded stores involving the introduction of new/upgraded external stores configurations. Since a typical combat aerial vehicle in service today is already operating at the edge of its flight characteristics envelope the addition of external payloads with a high drag index has a negative impact on the flight performance characteristics, such as increased turn radius and fuel consumption, reduced climb rate, maneuverability, turn rate, airspeed, operational range, effective operational ceiling, and the like. Based on these physics of flight it is can be readily assumed that a new/upgraded stores configuration will have some negative impact on the flight characteristics of the platform, in order to avoid potential damage to the high-value aerial vehicle and to the crew manning the aircraft it is imperative that each and every new/upgraded store configuration will be submitted to a series of comprehensive ground-based and in-flight tests in order to evaluate the aerial vehicle stores compatibility of any given configuration. The new/upgraded configuration is certified and approved for operational use only after the suitably collected test data proves the safe operability of the configuration.
The tests must evaluate the flight characteristics of an aerial vehicle resulting from the implementation of a new/upgraded stores configuration. The behavior of the platform in association with the tested stores configuration must be systematically evaluated by performing ground-based tests (engineering analysis, computer simulation, wind tunnel testing) and subsequent flight tests to be executed under a variety of flight conditions. The tests address such vital issues as safe stores carriage, safe stores release, safe carriage of combined stores, safe release of combined stores, emergency release, dynamic release and separation effects, weapon delivery accuracy, ballistic accuracy, limitations in the center of gravity range and margins, additional load effects, flutter, drag, aerodynamic stability and balance, size of radar and infrared signatures, and the like. Data collected during flight tests is in regard with the behavior and the performance of the platform in the variety of cases from a full loaded store configuration up to an asymmetric configuration resulting from partial store release, from unintended store release, and the like. If in any of the testing stages the results indicate unacceptable flight envelope deterioration or unacceptable functioning of the stores, then suitable structural modifications will be made on the stores, in the stores configuration or even in the aircraft frame and the tests are repeatedly performed. At the completion of the testing process, in accordance with the test data collected, the new/upgraded stores configuration is either certified, that is approved for operations by an appropriate certification board or is rejected as unsuitable for operations until further changes are made. It would be easily understood that the entire ground-based tests, flight tests and certification procedure loop is a highly complex, substantially cumbersome, and time-consuming process that involves very high expenses and very high risks.
Currently a new generation of advanced, powerful, miniaturized munitions is being developed and introduced. The utilization of these advanced weapon types, such as small smart bombs, and the like, is highly advantageous in terms of increased accuracy, reduced volume and weight and superior effectiveness. One disadvantage of the miniaturized munitions relates to the associated carrier means, such as unique miniaturized munitions-specific pods that are used as unique containers for the new weapons. The unique miniaturized munitions-specific pods have a limited payload capacity, aerodynamic inefficiency, high drag and negative dynamic release and separation characteristics. An additional drawback of the miniaturized munitions pertains to the fact that a particular weapon station is capable of supporting only one particular type of store for a specific mission. Thus, by necessity, a single miniaturized munitions-specific pod typically occupies an entire available weapon station, which is capable of supporting much higher loads. Due to the limited number of the weapon stations and the significantly reduced weight of the miniaturized munitions, the implementation of a stores configuration containing miniaturized munitions may result in the potential dissipation of the stores suspension potential and payload capacity potential of an aerial vehicle that was typically designed to support much higher loads.
It would be easily perceived by one with ordinary skill in the art that there is an urgent need for a cost-effective and low-risk system and method that would provide substantially more efficient payload capacity and substantially enhanced stores configuration flexibility for the majority of the current and prospective military aerial vehicles. The system and method should preferably exploit in the most advantageous manner the stores carriage potential of the aerial vehicles in an aerodynamically most effective manner. The system and method should flirter provide for the uploading of diverse stores having a substantially high volume that substantially preserves the aircraft's flight envelope without substantially increasing the radar/infrared signature of the vehicle. The system and method should provide the option of combining different stores carried on a single weapon station. The implementation of the system and method should further involve none or a minimum of airframe modifications, a minimum of stores management and control system changes, low costs, low risks, minimum training, and simplified, rapid, low-cost, low-risk testing, evaluation, and certification procedures.